Involvement of auxin distribution in root nodule development of Lotus japonicus
Involvement of auxin distribution in root nodule development of Lotus japonicus
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DOI：
10.1007/s00425-011-1385-0
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发表时间：
2011-03
期刊：
影响因子：
4.3
通讯作者：
Kojiro Takanashi;A. Sugiyama;K. Yazaki
中科院分区：
文献类型：
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作者：
Kojiro Takanashi;A. Sugiyama;K. Yazaki
豆科植物和根瘤菌之间的共生导致了新器官的发育，根瘤起到了固氮的作用。本研究利用分子遗传学工具和生长素抑制剂研究了生长素在莲花根瘤发育中的作用。分析生长素报告基因Gh3与β-葡萄糖醛酸苷酶(GUS)的融合表达。根瘤菌侵染后，在根瘤细胞第一次分裂的外皮层细胞中观察到GUS信号的产生。当根瘤发育到成熟时，在根瘤的维管组织中检测到强烈的GUS染色，这表明生长素明显参与了确定的根瘤的发育。生长素运输抑制剂(1-萘基邻苯二甲酸和三吲哚苯甲酸，TIBA)和新合成的生长素拮抗剂α-(苯乙基-2-酮)-吲哚-3-乙酸(PEO-IAA)影响根瘤的数量和发育。这些生长素抑制剂的常见表型变化是抑制皮孔的形成，皮孔通常是从根的外皮层在根瘤表面形成的。抑制皮孔形成与抑制根瘤维管束发育有关。这些结果表明，生长素是确定性结核以多方向方式正常发育所必需的。
The symbiosis between legume plants and rhizobia causes the development of new organs, nodules which function as an apparatus for nitrogen fixation. In this study, the roles of auxin in nodule development inLotus japonicushave been demonstrated using molecular genetic tools and auxin inhibitors. The expression of an auxin-reporter GH3 fused to β-glucuronidase (GUS) was analyzed inL. japonicusroots, and showed a strong signal in the central cylinder of the root, whereas upon rhizobium infection, generation of GUS signal was observed at the dividing outer cortical cells during the first nodule cell divisions. When nodules were developed to maturity, strong GUS staining was detected in vascular tissues of nodules, suggesting distinct auxin involvement in the determinate nodule development. Numbers and the development of nodules were affected by auxin transport inhibitors (1-naphthylphthalamic acid, NPA and triindobenzoic acid, TIBA), and by a newly synthesized auxin antagonist, α-(phenyl ethyl-2-one)-indole-3-acetic acid (PEO-IAA). The common phenotypical alteration by these auxin inhibitors was the inhibition in forming lenticel which is normally developed on the nodule surface from the root outer cortex. The inhibition of lenticel formation was correlated with the inhibition of nodule vascular bundle development. These results indicate that auxin is required for the normal development of determinate nodules in a multidirectional manner.